dendrogram from distance matrix

Dear all,
I am not a molecular evolutionist, however, for my thesis I need to
draw a dendrogram from % divergence. The data is from RFLP of my
gene using seven restriction enzymes and the sequence divergence
calculated using the Nei and Li algorithm. I know that this can be
done by converting the data into binary format, but this is a lot of
work for 54 alleles. I was wondering if there was an easier way of
doing it, straight from a distance matrix.
Thanks for your help
Sam king
mjkg at dna.bio.warwick.ac.uk